First edition 1939 (photo without drawings) - Second edition 1942 - Third edition 1949 Produced by Knoll - Fourth edition 1950 Produced by Slica di Recco - Fifth edition referring to the drawings of 12/04/1954 and 12/01/1955. The structural solution of this armchair is built starting from two sides with a trestle pattern, joined together by crosspieces. The upper element of the stand, which acts as an armrest, protruding overhang joins the other side, with a crossbar to support the backrest; among the other crosspieces placed in the center of the stand, the rear one acts as a fixing point for the seat surface and the front one as a free support, on which the seat can flex and slide according to the load carried.